Digital Odometer Using Atmega8

    In this project we will be using a reed switch to count the number of rotations of the wheel and thereby calculating the distance traveled. The micro-controller used is Atmega8 @ 8Mhz. The result is displayed in a 16x2 LCD. The coding is done using Arduino IDE. (How to program Atmega8 @ 8Mhz using Arduino IDE is illustrated in my friend's blog- Achu's blog ).

 

Reed Switch

   The reed switch is an electrical switch operated by an applied magnetic field. It was invented at Bell Telephone Laboratories in 1936 by W. B. Ellwood. It consists of a pair of contacts on ferrous metal reeds in a hermetically sealed glass envelope. The contacts may be normally open, closing when a magnetic field is present, or normally closed and opening when a magnetic field is applied. The switch may be actuated by a coil, making a reed relay, or by bringing a magnet near to the switch. Once the magnet is pulled away from the switch, the reed switch will go back to its original position.

                                       

    So if we know the diameter (D) of the wheel the distance traveled in one rotation is equal to the circumference of the wheel (π*D). So each time the reed switch is closed it is assumed that the wheel has completed one rotation and so has traveled a distance equal to the circumference of the wheel.

    The varying frequency signal should be decoded to get the number of rotations which is done in the code. 

Circuit Diagrams:

Reed Switch Circuit

Atmega8 LCD Interface

                So now we are all set with the hardware part now lets start coding...
                                   

4 DOF Robotic Arm With Gripper

My first robotic arm. Is working quiet nice. will upload the code soon.

RC Rover With Gripper

Work under progress.....Will update the details soon.....

Make Your Own PCB Driller

    Was thinking of making a small, lite weight and easy to use PCB driller for sometime. So today I stopped thinking and decided to do it. All of you can make one like this within no time. Here is some things you need:

• A dc motor
• A push-to-make switch
• An old torch
• An old lead pencil
• Some wires
• Double sided tape
• And some screws, a drill bit, a candle, match box etc etc......

 1.First of all you have to hack the lead pencil and take its inner parts out. 

 

2.Now take the end of the lead pencil. The part marked in the above picture will be used to hold the drill bit. Now heat the transparent end of this holder and insert it to the motor's shaft, as show in the below picture:

Kicad Files for Avr Programmer

        I had been trying to study Kicad for a few days. So here is my first work for you. Its a Usb Avr Programmer using Atmega8. 

Schematics

      Eventhough drawing the schematic is quite easy, i think developing the Pcb is quite difficult for a beginner. But its quite comfortable and offers many interesting features.

PCB

Model Of Mobile Communication Network (Theory)

The basic elements in a communication network

       As you all know a communication network consists of the users and the network elements to provide the service to the users. These network elements consists of the BTS, BSC, MSC, VLR, HLR, GMSC, PSTN etc. Hey dont worry seeing all these! I will explain it one by one to you all.

Mobile Station (MS)
       This refers to the physical phone itself. The phone must be able to operate on a GSM network. Older phones operated on a single band only. Newer phones are dual-band, triple-band, and even quad-band capable. Each phone is uniquely identified by the International Mobile Equipment Identity (IMEI) number. This number is burned into the phone by the manufacturer. The IMEI can usually be found by removing the battery of the phone and reading the panel in the battery well.

Base Transceiver Station (BTS)

       The BTS is the Mobile Station's access point to the network. It is responsible for carrying out radio communications between the network and the MS. It handles speech encoding, encryption, multiplexing (TDMA), and modulation/demodulation of the radio signals. It is also capable of frequency hopping. A BTS will have between 1 and 16 Transceivers (TRX), depending on the geography and user demand of an area. Each TRX represents one ARFCN. One BTS usually covers a single 120 degree sector of an area. Usually a tower with 3 BTSs will accommodate all 360 degrees around the tower. However, depending on geography and user demand of an area, a cell may be divided up into one or two sectors, or a cell may be serviced by several BTSs with redundant sector coverage. A BTS is assigned a Cell Identity. The cell identity is 16-bit number (double octet) that identifies that cell in a particular Location Area. The cell identity is part of the Cell Global Identification (CGI).The CGI is a number that uniquely identifies a specific cell within its location area, network, and country. The interface between the MS and the BTS is known as the Um Interface or the Air Interface.

Base Station Controller (BSC)

        The BSC controls multiple BTS. It handles allocation of radio channels, frequency administration, power and signal measurements from the MS, and handovers from one BTS to another (if both BTSs are controlled by the same BSC). A BSC also functions as a "funneler". It reduces the number of connections to

Model Of Mobile Communication Network

The Final Model

Seeing the heading most of you must be wondering why should someone need something like this when the real thing is with everyone! Ya You are right, I also thought like that at first. But the person who inspired us to do this project told us to conduct a survey on some people about how much they know about the working of the communication network. Actually the outcome was a little unexpected.( Hey I'm talking about common people!;-)) Most of them in-spite of using these things don't know how it works. So me along with my group members decided to take this project as our Main Project for our B.Tech Degree. We were guided through out the project by our Professor. Mrinalini C P, Government Engineering college, Sreekrishnapuram, Pallakad. My Team consists of of-course me. Sakir P M K, Fairoose E K, Femina Zachariya and Lavanya V. The course of work will be explained in the following posts.